There is known a (flip chip type) light-emitting device configured so that an element having a light-emitting layer of Group III nitride compound semiconductor is mounted on a support while a surface of the element on which a p-side electrode and an n-side electrode are formed is used as a mount surface. In this type light-emitting device, light emitted from the light-emitting layer of the light-emitting element passes through a light-transmissive substrate so as to be radiated to the outside. The electrodes of the light-emitting element are electrically connected to electrodes (an n layer and a p layer or wiring patterns) of the support through electrically conductive adhesive members respectively. High electric conductivity is required of the electrically conductive adhesive members. Generally, adhesive members of Au (Au bumps) are used as the electrically conductive adhesive members. Al, V, etc. can be used as the n-side electrode of the light-emitting element. On the other hand, Rh, etc. low in contact resistance and high in reflection efficiency can be used as the p-side electrode.
When Rh is used as the p-side electrode, adhesion of Rh to the Au bump is low. Therefore, a thick film of Au may be formed on a surface of the p-side electrode in advance to enhance adhesion of the p-side electrode to the Au bump. As a result, bonding strength between the light-emitting element and the support can be enhanced. When attention is paid to the n-side electrode, the surface of the n-side electrode is however made of Al etc. which is the material of the electrode. It cannot be said that bonding strength between the n-side electrode and the Au bump is sufficient. For this reason, there is still room for improvement in preservative characteristic or durability. There is also fear that a sufficient element function cannot be exhibited because failure occurs in bonding between the n-side electrode and the support. Furthermore, it is undesirable from the point of view of corrosion resistance that Al etc. which is the material of the electrode is exposed at the surface of the n-side electrode. When the electrodes one of which is made of Al while the other is made of Au have to be soldered, there is a further problem in solderability of the electrodes.
The invention is developed in consideration of the aforementioned problems and an object of the invention is to provide a Group III nitride compound semiconductor light-emitting element which is excellent in preservative characteristic or durability and which has a more stable element function.